"The recall notification is being issued out of an abundance of caution based on an isolated instance in which a single package of Fresh Express Hearts of Romaine Salad with a use by date of May 15 was confirmed positive for Salmonella in a random sample test conducted by the U.S. Food and Drug Administration," according to a company news release.

Salmonella is an organism that can cause fever, nausea, vomiting, abdominal pain and possibly bloody diarrhea in healthy individuals, and serious and sometimes fatal infections in young children, frail or elderly people and others with weakened immune systems.

Company officials issued a statement saying it is "highly unlikely" that any of the potentially affected salads are still on store shelves due to the expired use-by dates, but consumers might still have the product in their refrigerator and should immediately discard it.

The use-by date is found in the upper right hand corner of the package with the product code located immediately underneath. For Fresh Express Gourmet Cafe Salads, the use-by date and product code are located on the bottom of the salad bowl.

Affected consumers are eligible for a full refund by calling Fresh Express at 800-242-5472.

Fresh Express, which was founded in Salinas, Calif., is a wholly-owned subsidiary of Chiquita Brands International.